Thrust vector control system

ABSTRACT

A thrust vector control system for a rocket motor wherein a pair of rows of injection ports are provided circumferentially of the nozzle for injection of fluid thereinto. Means for selectively varying the rate of flow of the fluid injected thereby creating a nonstructural, variable positioned throat to vary thereby the direction of the rocket motor thrust vector.

United States Patent 1151 3,698,642 McCullough [4 1 Oct. 17, 1972 [s41THRUST VECTOR CONTROL SYSTEM 3,036,430 5/1962. Eggersetal; ..239/265.23

72 lnv t ZEd (115.1 ll 1 en or war ough Bngham PrimaryExaminer-SamuelFeinberg Utah Attorney-Thomas W. Brennan [73] Assignee:Thiokol Chemical Corporation,

Brim, p [57] ABSTRACT [22] Fil NOVA, 19 v A thrust vector control systemfor a rocket motor wherein a pair of rows of injection ports areprovided PP N04 592,089 circumferentially of the nozzle for injection offluid thereinto. Means for selectively varying the rate of flow of thefluid injected thereby creating a nonstruc- [52] US. Cl ..239/265.23,60/231 Hal, variable positioned throat to vary thereby the 5 l I Int.(J. "86 ml 25/46 direction f the rocket motor thrust vector [58! Fieldof Search ..239/265.17, 265.23; 60/230, v r r [56] References Cited 4Claims, Drawing Figures UNITED STATES PATENTS 3,000,178 9/1961 Logerot..239/265.23

TO PUMP I I 20 I2 VECTOR I PL MP 2 PATENTEDBBTIT I9 2 3,698,642

THRUS T VE C TOR FIG. 2

' PUMP INVENTOR. EDWARD E. MC CUL LOUGH l'WRFfM ATTORNEY THRUST VECTORCONTROL SYSTEM This invention relates to rocket motors and moreparticularly to a thrust vector control system for rocket motors.

The flight path of a rocket motor has heretofore been controlled byvarious means, among the most efficient of which is the so-calledsecondary injection thrust vector control method. A rocket controlsystem of this type is described in U.S. Pat. No. 3,273,801. The presentinvention provides an improved system whereby the thrust vector of arocket motor is controlled by varying the flow of fluid through two rowsof ports in the wall of the thrust nozzle of said rocket motor affordinggreater mechanical advantage, as will be more fully explained below. IAccordingly, it is an object of this invention to provide an improvedthrust vector control system for a rocket motor.

Another object of this invention is to provide a thrust vector controlsystem having no moving parts exposed to propellant gases.

The invention will be more readily understood by consideration of thefollowing description of a preferred embodiment thereof, in whichdescription reference is made to the accompanying drawing wherein: I

FIG. 1 is a fragmentary longitudinal sectional view of the aft end of arocket motor incorporating the preferred embodiment of the invention;and

FIG. 2 is a cross-sectional view of the same rocket, taken along theplane represented by line 2-2 in FIG. 1 and in the indicated direction.

Throughout the specification and the drawings, like reference numbersdesignate like parts.

As illustrated in FIG. 1, a preferred embodiment of the inventioncomprises a rocket motor, generally designated by the number 10, whichhas a convergentdivergent nozzle 12 mounted on the aft end of its casing14. For the purpose of interpretation of the claims appended hereto, thethroat plane of the nozzle is defined as that plane perpendicular to thelongitudinal axis of nozzle 12 at the point of the greatest constrictionof said nozzle. Thrust nozzle 12 is provided with a first row of fourports 16, each of which extends through the wall of said nozzle and isspaced apart at equal distances circumferentially thereof. Further, eachof said ports is equidistant longitudinally from the throat plane ofsaid nozzle.

Thrust nozzle 12 is also provided with a second row of ports 18, each ofwhich extends through the wall of said nozzle and is spaced apart atequal distances circumferentially thereof. Further, the ports of saidsecond row are spaced equidistant longitudinally from the ports of saidfirst row. Although in the embodiment illustrated the first row of portsis upstream and the second row of ports is downstream from the throatplane of nozzle 12, it is to be understood that in other embodimentsboth rows can be either upstream or downstream of said throat plane, orone of said rows can be located at said throat plane.

Four ducts 20 are communicatively connected to respective ones of theports 16, 18. A valve 22 is disposed in each duct to control fluid flowthrough the duct. Fluid is provided by conventional pump means notshown. Thus, during flight of the rocket fluid from the pump can bedelivered through any selected duct or through all ducts simultaneouslyat different flow rates and pressures controlled by valves 22. As willbe understood by those familiar with the art of secondary injection,flow of fluid through ports 16 and 18 creates shock waves which form agaseous, non-structural throat 24, illustrated in FIGS. 1 and 2 bybroken lines. When the injected fluid is directed against the propellantgas stream with equal force from all ports 16 and 18, the nonstructuralthroat will be concentric about the longitudinal axis of nozzle 12.However, by controlling the fluid flow through one or more ports thenon-structural throat can be located in any position and can be tiltedwith respect to the longitudinal axis of nozzle 12. For example, asillustrated in FIGS. 1 and 2, flow can be terminated in one of the portsof the first row and the flow through the other ducts regulated to forma nonstructural throat located and tilted as shown, changing the thrustvector of the rocket motor so that the rocket will pitch downward. Thoseskilled in the art will recognize that the invention can be utilized tomove the rocket in other directions, to change its velocity, and torotate it about its axis, the latter requiring at least two motors, ortwo thrust nozzles equipped with the invention.

The fluid injected through the ports can be a liquid or a gas.Preferably the fluid is an inert gas, such as helium, but either areactive gas or a liquid can be used.

While a preferred embodiment of the invention has been described andillustrated, it will be understood that various modifications andchanges may be made within the scope of the invention. For example,thrust vector control may be achieved in accordance with the inventionby a system having three ports in each row rather than four.

What is claimed is:

1. In a rocket motor having a convergent-divergent nozzle for expellingcombustion gases produced in said motor, the thrust vector controlsystem comprising:

a first row of flow parts extending through the wall of said nozzle,spaced apart circumferentially thereof and oriented therein so as toprovide a direction of entry of fluid flowing through said ports intosaid nozzle normal to the longitudinal axis of said motor, each of saidports being spaced equidistant longitudinally from the throat plane ofsaid nozzle;

a second row of ports extending through the wall of said nozzle, spacedapart circumferentially thereof and oriented therein so as to provide adirection of entry of fluid flowing through said ports into said nozzlenormal to the longitudinal axis of said motor, the ports of said secondrow being spaced equidistant longitudinally from the ports of said firstrow;

a plurality of ducts each communicatively connected to a respective oneof said ports;

means for causing fluid to flow under pressure in said ducts and throughsaid ports; and,

valve means in each of said ducts for selectively varying said fluidflowing through said ports, said fluid thereafter acting upon saidrocket motor combustion gases so as to form a nonstructural throattherearound, said throat tiltable with respect to said longitudinal axisin response to said selectively varied fluid flowing into said nozzlethrough said ports.

3 4 2. The thrust vector control system defined in claim gitudinallyfrom the throat plane of said nozzle; 1 wherein each of said first andsecond rows includes at injecting fluid into said nozzle in a directionnormal least three ports circumferentially spaced equidistant to thlongitudinal axis of said motor through a from each other.

3. The thrust vector control system defined in claim 5 1 wherein saidfluid is a gas and said means for causing said fluid to flow underpressure comprises a pump.

4. A method for controlling the thrust vector of a rocket motor having aconvergent-divergent nozzle for expelling combustion gases produced insaid motor second row of ports extending through the wall of said nozzleand spaced apart circumferentially thereof, the ports of said second rowbeing spaced equidistant longitudinally from the ports of said firstrow; selectively varying the rate of flow of said fluid through saidports; and directing said fluid comprising the steps leaving said portsin a direction normal to said injecting fluid into said nozzle in adirection normal longituduial axis Sald fluld thereafter acting to thelongitudinal axis of said motor through a on i g g so i: z i gi qg firstrow of ports extending through the wall of said tum i ma? i l e nozzleand spaced apart circumferentially thereof, respect tot e ongltu maaxlso Sal m0 each of said ports being spaced equidistant lon-

1. In a rocket motor having a convergent-divergent nozzle for expellingcombustion gases produced in said motor, the thrust vector controlsystem comprising: a first row of flow parts extending through the wallof said nozzle, spaced apart circumferentially thereof and orientedtherein so as to provide a direction of entry of fluid flowing throughsaid ports into said nozzle normal to the longitudinal axis of saidmotor, each of said ports being spaced equidistant longitudinally fromthe throat plane of said nozzle; a second row of ports extending throughthe wall of said nozzle, spaced apart circumferentially thereof andoriented therein so as to provide a direction of entry of fluid flowingthrough said ports into said nozzle normal to the longitudinal axis ofsaid motor, the ports of said second row being spaced equidistantlongitudinally from the ports of said first row; a plurality of ductseach communicatively connected to a respective one of said ports; meansfor causing fluid to flow under pressure in said ducts and through saidports; and, valve means in each of said ducts for selectively varyingsaid fluid flowing through said ports, said fluid thereafter acting uponsaid rocket motor combustion gases so as to form a nonstructural throattherearound, said throat tiltable with respect to said longitudinal axisin response to said selectively varied fluid flowing into said nozzlethrough said ports.
 2. The thrust vector control system defined in claim1 wherein each of said first and second rows includes at least threeports circumferentially spaced equidistant from each other.
 3. Thethrust vector control system defined in claim 1 wherein said fluid is agas and said means for causing said fluid to flow under pressurecomprises a pump.
 4. A method for controlling the thrust vector of arocket motor having a convergent-divergent nozzle for expellingcombustion gases produced in said motor comprising the steps of:injecting fluid into said nozzle in a direction normal to thelongitudinal axis of said motor through a first row of ports extendingthrough the wall of said nozzle and spacEd apart circumferentiallythereof, each of said ports being spaced equidistant longitudinally fromthe throat plane of said nozzle; injecting fluid into said nozzle in adirection normal to the longitudinal axis of said motor through a secondrow of ports extending through the wall of said nozzle and spaced apartcircumferentially thereof, the ports of said second row being spacedequidistant longitudinally from the ports of said first row; selectivelyvarying the rate of flow of said fluid through said ports; and directingsaid fluid leaving said ports in a direction normal to said motorlongitudinal axis, said fluid thereafter acting on said combustion gasesso as to form a nonstructural throat therearound, said throat tiltablewith respect to the longitudinal axis of said motor.